Lord George Gordon Byron's poem "She Walks in Beauty" exemplifies many of the typical features of Romantic poetry.
The first way in which the poem follows conventions typical of Romantic poems is in its natural setting. The woman is portrayed as walking alone in a natural environment, and nature itself is seen as a source and standard of beauty.
The next characteristic of the poem that is typically Romantic is its celebration of innocence; the woman is praised for a childlike innocence and purity. In fact, it is this characteristic of her soul that makes her beautiful, not just her appearance.
The insistence on virtue as an inner state rather than as expressed in outward deeds also marks the increased focus on selfhood that is typical of the Romantic period. We don't actually observe the woman doing anything virtuous such as carrying food to the poor or nursing an injured kitten, only as having a virtuous expression on her face.
Finally, the type of beauty described is not one of perfect symmetry, artfully tended, but somewhat more natural, something admired by the Romantics.